I had upgraded a 10g database to 11.2.0.2. I could never get the dbconsole working for this until few days back when someone else had same issue and needed help.
The issue was dbconsole was not starting up.
Note: I have removed actual URL and hostname with "*" symbol to maintain privacy
.$ emctl start dbconsole
Oracle Enterprise Manager 11g Database Control Release 11.2.0.2.0
Copyright (c) 1996, 2010 Oracle Corporation. All rights reserved.
https://*************:1158/em/console/aboutApplication
Starting Oracle Enterprise Manager 11g Database Control ............................................................................................. failed.
------------------------------------------------------------------
Logs are generated in directory /oracle/product/11.2.0/************_******/sysman/log
$ emctl status dbconsole
Oracle Enterprise Manager 11g Database Control Release 11.2.0.2.0
Copyright (c) 1996, 2010 Oracle Corporation. All rights reserved.
https://***************:1158/em/console/aboutApplication
EM Daemon is not running.
------------------------------------------------------------------
Logs are generated in directory /oracle/product/11.2.0/*************_******/sysman/log
Even though status is "Em Daemon is not running", I see login screen for https://************:1158/em
So tried logging in using sysman:
As the agent should run on port 3938, which is not running causing below errors when dbconsole service is trying to communicate with the agent:
from emdctl.trc:
2012-01-17 10:59:20,817 Thread-287350144 WARN http: nmehl_connect_internal: connect failed to (************:3938): Connection refused (error = 111)
2012-01-17 10:59:20,818 Thread-287350144 ERROR main: nmectla_agentctl: Error connecting to https://***************:3938/emd/main. Returning status code 1
So we need to find why the agent is not running. Checked agabend.log which shows:
The agentTZRegion value in /oracle/product/11.2.0/*************_*******/sysman/config/emd.properties is not in agreement with what agent thinks it should be.Please verify your environment to make sure that TZ setting has not changed since the last start of the agent.At the same time, emdb.nohup shows:
If you modified the timezone setting in the environment, please stop the agent and exectute 'emctl resetTZ agent' and also execute the script mgmt_target.set_agent_tzrgn(<agent_name>, <new_tz_rgn>) to get the value propagated to repository.
----- Tue Jan 17 10:57:24 2012::omsRecvDir is set? = 1
---------- Tue Jan 17 10:57:24 2012::osname is linux
---------- Tue Jan 17 10:57:24 2012::Console Launched with PID 25486 at time Tue Jan 17 10:57:24 2012 ---------- Tue Jan 17 10:57:24 2012::heap size used is 384M
---------- Tue Jan 17 10:57:24 2012::perm size used is 400M
---------- Tue Jan 17 10:57:24 2012::joptions used are -server -Xmx384M -XX:MaxPermSize=400M -XX:MinHeapFreeRatio=20 -XX:MaxHeapFreeRatio=40
-----sh: line 1: 25491 Segmentation fault (core dumped) /oracle/product/11.2.0/bin/emdctl validateTZ agent US/Eastern > /oracle/product/11.2.0/************_******/uunUBBW0Yo 2>&1
----- Tue Jan 17 10:57:25 2012::Mismatch detected between timezone in env (US/Eastern) and in /oracle/product/11.2.0/************_******/sysman/config/emd.properties (US/Eastern). Forcing value to latter..
-----sh: line 1: 25524 Segmentation fault (core dumped) /oracle/product/11.2.0/bin/emdctl validateTZ agent US/Eastern > /oracle/product/11.2.0/************_******/kuoO8Ru0vA 2>&1
----- Tue Jan 17 10:57:26 2012::The agentTZRegion value in /oracle/product/11.2.0/************_******/sysman/config/emd.properties is not in agreement with what agent thinks it should be.Please verify your environment to make sure that TZ setting has not changed since the last start of the agent.If you modified the timezone setting in the environment, please stop the agent and exectute 'emctl resetTZ agent' and also execute the script mgmt_target.set_agent_tzrgn(<agent_name>, <new_tz_rgn>) to get the value propagated to repository
-----
Strange thing is there is NO mismatch, both shows (US/Eastern). Not sure what was happening. I checked /oracle/product/11.2.0/************_******/sysman/config/emd.properties for agentTZRegion value:
$ cat /oracle/product/11.2.0/************_******/sysman/config/emd.properties | grep agentTZ
agentTZRegion=US/Eastern
Found MOS document "Dbconsole 11.2 Does Not Start Logs Shows Timezone Mismatch (Doc ID 1329914.1)".
Oracle instant client was installed on the same Oracle RDBMS Home, removed just that using OUI and now dbconsole is working fine.
If you have similar situation and had created new Database using DBCA. You might have seen below warning message by dbca.


